The present Application claims the benefit of the priority of Japanese 11-048223, filed Feb. 25, 1999.
The present Invention is directed to an electrical connection box having a guide for a wire harness. More specifically, the guide directs the wire harness out of the box for further connection to various electrical elements used particularly in automotive electrical circuits. The device fixes the harness by the use of a tying band to prevent undesired movement.
Conventional electrical connection boxes are located in automobiles in order to house the various electrical devices used in automotive circuits, such as relays and fuses. In addition, these boxes serve as branching points for wire harnesses.
FIGS. 7 and 8 show a typical prior art connection box having a wire guide projecting therefrom. Connection box 50 is comprised of cover 51 and housing 52. The desired electrical elements (not shown) are within the housing. Cut out 52B is provided in front 52A, which is one of the outer perimeter surfaces of housing 52. The cut out extends from the upper end to the lower end of front 52A. Wire guard 53 is in the shape of a half-cylinder extending diagonally downward from front 52A, with groove 54 facing up. This groove is continuous with cut out 52B. Flange 55, with its plane parallel to front 52A, is located at the end of wire guide 53 remote from front 52A. The angle of wire guide 53 to front 52A is determined by the nature and location of the electrical elements within housing 52, as well as the electrical elements outside the housing to which the wire harness is to be connected.
As best shown in FIG. 8, wire harness 57 extends from the unillustrated electrical elements in housing 52 through cut out 52B and is restricted by the semi-circular groove of guide 53. The wire harness is retained in guide 53 by tying band 56. The band is wrapped around guide 53 and its position is determined by flange 55. In other words, flange 55 defines the position at which wire harness 57 is located relative to wire guide 53, while also preventing tying band 56 from slipping off the end of the wire guide.
In order to fix wire harness 57 to wire guide 53, it is best that tying band 56 be tightened in the direction indicated by arrow b, i.e. perpendicular to wire guide 53. This is most reliable and prevents loosening. However, due to the usual space limitations within the engine compartment of an automobile (where the connection box is usually mounted), the force is actually applied in the direction of arrow a. This is required because of the presence of other elements crowded in the engine compartment.
As a result, gap 57A is formed between the wire harness and the tying band, and gap 53A is formed between the wire guide and the tying band. Thus, if vibration is present (as is usually the case), tying band 56 can slide down wire guide 53 to assume the position shown in broken lines. Thus, the band becomes loose on the guide and, in extreme cases, can even slip over flange 55. As a result, wire harness 57 is no longer secure and can move out of its desired position.
Since the various electrical elements to which wire harness 57 is connected are fixed, any movement by the harness causes problems of undue tension or too much slack, thus leaving the assembly open to electrical problems. Alternatively, the length of wire harness 57 will have to be adjusted or the harness moved back to its original position in order to provide reliable connections. It may even be necessary to reattach the tying band.
It is the object of the present Invention to provide an electrical connection box wherein the wire harness is reliably and firmly affixed to the wire guide. In a first embodiment, an electrical connection box is provided wherein the wire guide projects outwardly from the front of the box and is adapted to receive the wire harness. An opening is located in the wire guide and the tying band passes through the opening and around the wire harness and wire guide. Thus, when the band is tightened, the harness is secured and retained in its position regardless of the vibration to which it is subjected. In a preferred form of the Invention, there are two openings, one adjacent each of the edges of the wire guide and the tying band passes through both. This provides added security.
The tying band desirably comprises a strap having a head adjacent one end with a hole therethrough. The strap, after passing around the wire harness and wire guide and through the opening(s), is inserted into the hole and retained either by friction or a ratchet and pawl mechanism. It has been found useful, in this embodiment of the Invention, that the wire guide project from the lower end of the cut out. The wire harness passes through the cut out and rests on the upper side of the wire guide.
In a second embodiment of the present Invention, there is an insertion ring, mounted on the guide, having an opening parallel to the surface of the guide and perpendicular to the axis of the wire harness. The ring is either fixed to the wire guide or the wire guide constitutes one side of the ring. The tying band passes through the opening in the ring and secures the wire harness thereto. Since the ring is fixed to the guide, the band is secure in its position and cannot move.
When the wire guide is located at the upper end of the cut out, the wire harness is affixed to the underside thereof. Thus, by locating the wire guide at either the top or the bottom of the cut out, the wire harness can be located either against the bottom or top surface thereof. This provides desirable flexibility in the design and assembly of the connection box.
In a third embodiment of the Invention, the wire guide has an insertion opening adjacent one edge and a notch in the other edge opposite the insertion opening. The tying band passes around the wire harness, through the opening and is in the notch.
In a fourth embodiment of the present Invention, the wire guide is provided, at its remote end, with a flange substantially parallel to the front of the connection box. An insertion ring is provided alongside the flange and the band is passed therethrough. Preferably, there are two such insertion rings, one adjacent each edge of the wire guide. In such a case, the band passes through both. There can be additional insertion rings through which the tying band passes for still further safety and reliability. It has also been found desirable to form these insertion rings so that a portion of the wire guide constitutes one side of the ring.
For additional strength, a pair of side walls can be located adjacent the edges of the guide at the end near the connection box in any of the foregoing embodiments. The walls are affixed to both the front of the connection box and the wire guide. If desired, the wire guide can be arcuate in cross section so that it at least partially surrounds the wire harness. This will provide still further security.